U.S. Pat. Nos. 4,540,110; 4,527,726; and 4,500,025 and U.S. Pat. No. 4,569,469 filed Feb. 15, 1985, describe generally the same types of bone stapling devices as the device described in this application and describe and claim numerous novel features of such devices which facilitate driving staples into bone portions during surgery.
Generally, the staplers described in those patents and application and in this application are adapted for use with generally U-shaped staples. The staplers comprise (1) a barrel assembly including a first housing part having a passageway extending from an inlet opening to an outlet opening, adapted to guide a single staple moved from the inlet to the outlet opening with the distal ends of its legs leading and having a socket adapted to releasably receive a cartridge containing staples at the inlet opening, and a driver having a contact end portion adapted to engage the central portion of the staple, the driver being mounted on the first housing part for sliding movement between a load position with the driver spaced from the socket and inlet opening to afford movement of one of the staples into the passageway, along the passageway with the contact end portion pushing the staple, to an eject position at which the contact end portion of the driver pushes the staple out the outlet opening while restricting rotation of the driver relative to the first housing part; (2) a handle assembly including a second housing part and drive means including a piston assembly mounted on the second housing part and adapted to be manually activated for moving the piston assembly between first and second positions; and (3) means for releasably attaching together the barrel and handle assemblies including means for releasably attaching the first and second housing parts and for releasably attaching together the piston assembly and the inner end portion of the driver so that movement of the piston assembly between its first and second position will cause corresponding movement of the driver between its load and eject position to move the staple from the inlet to the outlet opening.
While those prior art means for releasably attaching together the barrel and handle assemblies afforded using different barrel assemblies on the same handle assembly to thereby drive staples of different sizes, the design of those means caused the stapler to be more difficult to clean and required more length axially of the driver and piston assembly than might otherwise be desired. Also, the barrel assembly could only be attached so as to be oriented in one of four positions with respect to the barrel assembly, thereby greatly limiting the possible orientations of staples to be driven with respect to the hand of a user grasping the handle assembly.